补骨脂素对绝经后大鼠骨质疏松及PI3K/Akt/mTOR信号通路的影响

目的:研究补骨脂素对绝经后大鼠骨质疏松及磷脂酰肌醇3激酶(PI3K)/蛋白激酶B(Akt)/哺乳动物雷帕霉素靶蛋白(mTOR)信号通路的影响。方法:将60只健康雌性SD大鼠随机分为正常组、模型组、阳性对照组(0.09 mg/kg雌二醇)和补骨脂素低、中、高剂量组(22、44、88 mg/kg),每组10只。除正常组外,其余各组大鼠均采用卵巢摘除去势法建立绝经后骨质疏松模型。术后正常饲养2个月,正常组和模型组大鼠灌胃等体积生理盐水,各药物组大鼠灌胃相应药液;灌胃体积均为0.005 mL/g,每天1次,连续98天。末次给药24 h后,测定大鼠右侧下肢股骨和椎骨的骨密度,血清中钙离子、骨钙素、Ⅰ型前胶原N端前肽(P1NP)含量和骨形态发生蛋白2(BMP2)、血管内皮生长因子(VEGF)水平,以及股骨组织中PI3K、Akt、mTOR mRNA及蛋白的表达水平。结果:与正常组比较,模型组大鼠股骨和椎骨的骨密度以及血清中钙离子、骨钙素、P1NP含量和BMP2、VEGF水平均显著降低,PI3K、Akt、mTOR mRNA及蛋白的表达水平均显著升高(P<0.05或P<0.01)。与模型组比较,补骨脂素中、高剂量组和阳性对照组大鼠股骨和椎骨的骨密度以及血清中钙离子、骨钙素、P1NP含量和BMP2(补骨脂素中剂量组除外)、VEGF(补骨脂素中剂量组除外)水平均显著升高,各药物组PI3K、Akt、m TOR mRNA(补骨脂素低剂量组除外)及蛋白表达水平均显著降低(P<0.05或P<0.01),且高剂量组股骨骨密度和钙离子、BMP2水平以及PI3K蛋白表达水平均显著高于阳性对照组(P<0.05),mTOR mRNA表达水平显著低于阳性对照组(P<0.05)。结论:补骨脂素可改善绝经后大鼠的骨质疏松,其机制可能与抑制PI3K/Akt/mTOR信号通路有关。

Effect of Psoralen on Osteoporosis in Postmenopausal Rats and PI3K/Akt/m TOR Signaling Pathway

OBJECTIVE:To study the effect of psoralen on osteoporosis in postmenopausal rats and PI3 K/Akt/mTOR signaling pathway.METHODS:Totally 60 healthy female SD rats were randomly divided into normal group,model group,positive control group(0.09 mg/kg estradiol),psoralen low-dose,medium-dose and high-dose groups(22,44,88 mg/kg),with 10 rats in each group.Except for normal group,the other groups were ovariectomized to establish Postmenopausal osteoporosis model.After 2 months of normal feeding after operation,normal group and model group were given the constant volume of normal saline intragastrically,and administration groups were given the corresponding solution intragastrically;the volume was 0.005 mL/g,once a day,for consecutive 98 days.24 h after last administration,the BMD of femur and vertebra of right lower extremities in rats was determined.The contents of serum calcium,osteocalcin and P1 NP,the serum levels of BMP2 and VEGF were determined;mRNA and protein expression of PI3 K,Akt and m TOR in femur tissue were detected.RESULTS:Compared with normal group,BMD of femur and vertebra,serum contents of calcium,osteocalcin,P1 NP and serum levels of BMP2,VEGF in model group were decreased significantly,while the m RNA and protein expression of PI3 K,Akt and mTOR were increased significantly(P<0.05 or P<0.01).Compared with model group,BMD of femur and vertebra,serum levels of calcium,osteocalcin,P1 NP and serum levels of BMP2(except for psoralen medium-dose group),VEGF(except for psoralen medium-dose group)were increased significantly in psoralen medium-dose and high-dose groups,positive control group,while the mRNA expression(except for psoralen low-dose group)and protein expression of PI3 K,Akt and mTOR in administration groups were decreased significantly(P<0.05 or P<0.01);BMD of femur,serum levels of calcium,BMP2 and PI3 K protein expression in psoralen high-dose group were significantly higher than positive control group(P<0.05),and mTOR m RNA expression in psoralen high-dose group was significantly lower than positive control group(P<0.05).CONCLUSIONS:Psoralen can improve osteoporosis in postmenopausal rats,the mechanism of which may be associated with inhibiting PI3 K/Akt/mTOR signaling pathway.